Inspired by the maxillary mouthparts of longicorn beetles, four types of bionic cutters were designed in this research to address the prevalent issues of high cutting resistance and severe stubble damage encountered during alfalfa harvesting. Finite element simulation was utilized to assess the structural integrity and cutting performance of these bionic cutters. Additionally, bench tests were conducted on a homemade stem-cutting force measurement and control rig to evaluate their effectiveness. The results indicated: (1) the bionic cutters achieved a reduction in maximum equivalent force ranging from 20.9% to 49.2% and a decrease in maximum deformation from 31.4% to 64.1% compared to conventional cutters; (2) the maximum cutting resistance of alfalfa stems was reduced by 28.6%, 43.9%, 52.4%, and 38.6%, significantly enhancing the flatness of the cut surfaces; (3) orthogonal bench tests demonstrated that the type of cutter and the slip-cutting angle significantly influenced the maximum cutting resistance of the stems (p < 0.01), with the optimal configuration being bionic cutter c, a slip-cutting angle of 10°, and a rotational speed of 2600 rpm. In conclusion, bionic cutters demonstrate substantial advantages in reducing maximum cutting resistance and improving the flatness of alfalfa stubble, suggesting their potential for widespread application and adoption.

The work aims to realize low-damage cutting of Alfalfa stalk. The self-sharpening blades of gradient material were prepared by 40 Cr steel, then heat-treating the flank surface by carbon-nitron-boronized with a rare elements catalysis technique. The biological characteristics of Alfalfa incision self-healing and regeneration process were analyzed in order to compare the cutting effects of different blades. After treatment with carbon-nitron-boronized with rare elements catalysis, the flank surface and tip point of blades were coated by boride layer and carbonitriding layer. The composition, microstructure and properties of the carbon-nitron-boronized layer demonstrated a gradient distribution state, and had good wear resistance. A kinetic model for the formation of the carbon-nitron-boronized layer was proposed. The initial stage of heat-treatment was mainly a carbonitriding process. When continuous and compact boride was formed on the surface, it was mainly boridized. The results of field experiment indicated that compared with the commercial blades, the self-sharpening blades have excellent properties as wear resistance and long service life. In addition, the cut damage caused by the self-sharpening blades was less, the self-healing and regeneration process of Alfalfa stalk was normal, and the regeneration duration was greatly shortened. The blades with carbon-nitron-boronized heat-treatment could form the self-sharpening characteristics, always maintaining the cutting sharpness, and realized the low-damage cutting of Alfalfa stalk.